Fat-liquoring agents for leather and skins

ABSTRACT

A FAT-LIQUORING AGENT FOR LEATHER AND SKINS CONTAINING AS AN ACTIVE SUBSTANCE AT LEAST 10% BY WEIGHT, OF TOTAL ACTIVE SUBSTANCES, OF A CHLORINATION PRODUCT OF AN ESTER OF A HIGHER FATTY ACID HAVING FROM 8 TO 24 CARBON ATOMS, SAID CHLORINATION PRODUCT HAVING A CHLORINE CONTENT OF FROM 10% TO 40% BY WEIGHT AND HAVING SUBSTANTIALLY NO FREE DOUBLE BONDS. THE METHOD OF FAT-LIQUORING AND THE FAT-LIQUORED LEATHER AND SKINS ARE ALSO A PART OF THE INVENTION. THE FAT-LIQUORING AGENTS OF THE INVENTION HAVE A GOOD ABSORPTION ON LEATHER FIBERS AS WELL AS AN EXCELLENT RESISTANCE TO LIGHT AND OXIDATION.

United States Patent O l 3,724,999 FAT-LIQUORING AGENTS FOR LEATHER AND SKINS Werner Stein, Erkrath-Unterbach, and Jurgen Plapper and Wolf-Dieter Willmund, Dusseldorf-Holthausen, Germany, assignors to Henkel & Cie G.m.b.H., Dusseldorf, Germany No Drawing. Filed Sept. 8, 1970, Ser. No. 70,526 Claims priority, application Germany, Sept. 16, 1969, P 19 46 723.3 Int. Cl. C14c 9/02 US. Cl. 8-94.23 10 Claims ABSTRACT OF THE DISCLOSURE A fat-liquoring agent for leather and skins containing as an active substance at least 10% by weight, of total active substances, of a chlorination product of an ester of a higher fatty acid having from 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40% by weight and having substantially no free double bonds. The method of fat-liquoring and the fat-liquorcd leather and skins are also a part of the invention. The fat-liquoring agents of the invention have a good absorption on leather fibers as well as an excellent resistance to light and oxidation.

THE PRIOR ART Leather and skin fat-liquoring agents emnlsifiable in water are generally prepared by sulfation of unsaturated natural or synthetic fats, oils or waxes with the usual sulfation agents. As a rule, the sulfation is only carried so far that a sufficient emulsifiability in water is attained, therefore the snlfation products obtained usually still possess a considerable residual iodine value. However, both the stability to oxidation and consequently the stability on storage of the fat-liquoring agents and the resistance to light of the leather fat-liquored therewith are affected unfavorably by the unsaturated character of these agents.

This disadvantage is removed according to the German Pat. No. 1,278,681 by reducing the number of double bonds by 20% to 70% by adding chlorine onto the unsaturated starting substances. The sulfation following thereon and applied to the residual double bonds provides fat-liquoring agents with improved properties as regards their stability to light and storage.

Besides these ionic products with their own emulsifiability in water, neutral water-insoluble products, such as natural or synthetic fats, oils or waves, in combination with water-emulsifiable products or with emulsifiers are also used as leather fat-liquoring agents, a less dry, more supple and greasier leather being thus obtained. Such combinations of substances, however, have certain drawbacks, such as a lack of resistance to light and oxidation, which again is due to the presence of double bonds. Moreover, the non-ionic or neutral fatty fractions tend to migrate in the leather to a considerable extent, owning to which, if the leather is more heavily fat-liquored, fat stains or fatty spew or scum may be formed. Also, such neutral oil fractions are relatively easily removed by water and especially by solvents, whereupon the fat-liquoring effect is annulled.

The disadvantage of the above-mentioned fat-liquoring agents can be more or less largely avoided by the use of polychlorinated paraffin hydrocarbons. The adhesion of such compounds in the plaited leather fibers is indeed better than in the case of the previously mentioned products, but the leather so treated has a relatively dry, harsh handle, which in many cases is a drawback to its use.

OBJECTS OF THE INVENTION The invention has as its object fat-liquoring agents for 3,724,999 Patented Apr. 3, 1973 leather which may avoid the abovementioned disadvantages.

In a further object, the present invention provides a process for treating leather comprising treating said leather with an agent as described immediately above.

Another object of the invention provides a fat liquoring agent for leather and skins containing as an active substance at least 10% by weight, of total active substances, of a chlorination product of an ester of a higher fatty acid having from 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40% by weight and having substantially no free double bonds.

A further object of the invention is the production of a fat-liquored leather using the above fat-liquoring agent, which leather has an excellent resistance to light and oxidation.

These and other objects of the invention will become more apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION According to the present invention there is provided a fat-liquoring agent for leathers comprising as active substance a chlorination product of an ester of a higher fatty acid having 8 to 24 carbon atoms, said product having a chlorine content of from 10% to 40% by weight and possessing substantially no free double bonds.

Owing to the absence of double bonds, the stability to light and oxidation of the fat-liquoring agents of the invention is very good. Their adhesion to the leather fibers is excellent, so that they do not migrate and form stains or sweat. The fatty substances also show good resistance against the action of solvents. The leathers treated according to the invention are also marked by a specially pleasant, soft, and greasy handle, which is probably due to the presence of ester groups in the fat-liquo-ring agents claimed.

The fat-liquoring agents for leather of the present invention contain, as active substances, at least 10% up to by weight of the active substances, of the aforesaid chlorinated esters of higher fatty acids having 8 to 24 carbon atoms. The remainder of the active substances present, if any, are other conventional fat-liquoring agents.

The fat-liqu-oring active substances of the invention are preferably chlorination products of esters of olefinicallyunsaturated higher fatty acids having from 8 to 24 carbon atoms with alcohols selected from the group consisting of alkanols having 1 to 4 carbon atoms, alkanediols having 2 to 6 carbon atoms, alkanetriols having 3 to 6 carbon atoms, alkanetetraols having 4 to 6 carbon atoms, hexanehexols, alkanols having from 8 to 24 carbon atoms and alkenols having 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40%, preferably from 20% to 30%, by weight, no sulfate groups, and having substantially no free or olefinic double bonds.

Suitable starting substances for the subsequent chlorination are the naturally occurring esters of higher molecular Weight fatty acids having from 8 to 24, preferably 10 to 20 carbon atoms and their mixtures, such as are present, for example, in natural fats or oils. Fats or oils with a content of monoor poly-unsaturated fatty acids are preferred. Examples of these include: coconut oil, soya oil, cottonseed oil, rape oil, linseed oil, castor oil, sunflower seed oil, olive oil, neats foot oil, peanut oil, herring oil, cod oil, shark liver oil, whale oil, tallow or lard, as well as naturally occurring wax esters, such as for example, sperm oil. However, starting substances are also suitable which do not contain unsaturated fatty acids, or whose content of unsaturated fatty acids has been reduced, for example saturated fats obtained by squeezing out, crystallizing out, or by distillation or obtained by partial or complete hardening of natural fats or oils.

Further, synthetically prepared esters from saturated or unsaturated fatty acids with 8 to 24, preferably 10 to 20 carbon atoms, such as decanecarboxylic acid, palmitic acid, stearic acid, behenic acid, dodecenecarboxylic acid, oleic acid, linoleic acid or linolenic acid, with monoor polyhydric aliphatic alcohols with 1 to 6 carbon atoms such as, for example, alkanols such as methanol, ethanol, isopropanol, butanol, alkanediols such as ethyleneglycol, 1,2-propyleneglycol, alkanetrios such as glycerin, alkanetetraols such as pentaerythritol or hexanehexols such as sorbitol, are used as starting substances for the chlorination. In addition, synthetic esters can also be used in which both the acid and the alcohol part has a higher hydrocarbon residue containing 8 to 24 carbon atoms, suc as alkyl alkenoates and alkenyl alkenoates as for example oleyl oleate.

On account of their easy availability, the natural animal and vegetable fats, oils or waxes and also the interesterification products with lower monohydric aliphatic alcohols, preferably alkanols having 1 to 6 carbon atoms, prepared therefrom are preferred as starting substances.

The chlorination of the starting substances is carried out in known way. The generally usual methods of chlorine addition are used, as for example, passing gaseous chlorine into the starting material to be chlorinated, while in some cases the charge may be diluted with an organic solvent, preferably a perchlorinated hydrocarbon, as, for example, carbon tetrachloride. The chlorine can also be diluted by inert gases, as, for example, nitrogen. In general the procedure is firstly to chlorinate at room temperature or moderately elevated temperature until any double bonds present are saturated and then passing the chlorine in at temperatures between about 40 and 100 C. and continued until the desired degree of chlorination with substitution of hydrogen atoms is reached. It is advisable, at least at the beginning of the substitution chlorination, to allow the light from a mercury vapor lamp or other ultra-violet light source to act. Advantageously the exposure is continued until the end of the chlorination. In each case care is taken by corresponding cooling that the heat of reaction formed is removed, in order to avoid harm through side reactions.

Substantially all the double bonds present in the starting materials should be saturated by the chlorination process and a chlorine content of at least about 10, preferably 20 to 30% by weight by attained in the end product. The degree of chlorination can be increased up to a fraction of about 40% by weight of chlorine in the end product.

Examples of suitable products are the chlorination products of tallow fatty acid methyl esters, rape oil fatty acid methyl esters, methyl oleate, train oil fatty acid methyl esters, tallow fatty acid ethyl esters, propyl oleate, herring oil, beef tallow, sperm oil, rape oil, peanut oil, castor oil, coconut oil and the like with a content of 20 to 30% by weight of chlorine. The chlorination also converts solid starting materials into the liquid state, so that chlorination products with relatively low melting points are obtained, which is specially advantageous for the use of the products as leather fat-liquoring agents.

It has been found expedient to stabilize the products in known way by the addition of 0.5% to by weight, based on the chlorinated products, of an epoxy compound. Hydrogen chloride residues, which are formed during the chlorination, are hereby rendered harmless and the fresh formation of free hydrogen chloride by the action of light or the like is stopped. Suitable stabilizers are, for example, glycide, epichlorohydrin, 1,2-3,4-diepoxybutane, vinylcyclohexene-diepoxide, glycidyl ethers of monoor polyhydric alcohols, for example of ethyleneglycol, glycerin, or sorbitol. However, epoxidized fatty substances are specially suitable, as for example, epoxidized natural fats or oils such as epoxidized soya oil, epoxidized linseed oil, or epoxidized butyl oleate, since these themselves possess fat-liquoring properties and increase the suppleness and stability to solvents of the treated leather.

The products are applied in the usual way, for example in the form of aqueous emulsions or in water-free form, for example in the form of organic solutions. The emulsification in water is carried out by means of emulsifiers, for example anionic higher fatty alcohol sulfates or alkylor alkylaryl-sulfonates, or with non-ionic products of addition of ethylene oxide to higher fatty alcohols or alkyl phenols containing 10 to 20 carbon atoms. Preferably, however, sulfation products of fats and oils are used which themselves possess the character or properties of leather fat-liquoring agents, as for example, the sulfation products obtained by sulfation of natural or synthetic fats, oils or waxes or those according to the German Pat. No. 1,278,681. The proportion of the products according to the invention in the fat-liquoring agent mixture should preferably amount to 10% to 40% by weight.

Preferred as the fat-liquoring agents of the invention are aqueous emulsions containing from 1 to 10% of active substances, said active substances consisting essentially of from 10% to 50% by weight of the chlorination products of esters of olefinically-unsaturated higher fatty acids having from 8 to 24 carbon atoms with alcohols selected from the group consisting of alkanols having 1 to 4 carbon atoms, alkanediols having 2 to 6 carbon atoms, alkanetriols having 3 to 6 carbon atoms, alkanetetraols having 4 to 6 carbon atoms, hexanchexols, alkanols having from 8 to 24 carbon atoms and alkenols having 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40%, preferably from 20% to 30%, by Weight, no sulfate groups, and having substantially no free or olefinic double bonds, from 0.5% to 5% by weight of an epoxidized ester of a higher olefinically-unsaturated fatty acid with an alcohol selected from the group consisting of glycerol and alkanols having from 1 to '6 carbon atoms, and from to 50% by weight of conventional anionic fat-liquoring agents.

The co-use of further customary leather treatment compositions, for example unsulfated oils or fats, such as fish oil, sperm oil, neats foot oil and the like, or synthetic fat-liquoring agents such as chlorinated paraffins, paraflin sulfonates, or mineral oils and the like may also be advantageous. Here again, the proportion of the products according to the invention should preferably amount to 10% to 40% by weight.

Instead of aqueous emulsions, the products may also be used in the form of their organic solutions, prepared by dissolving the substances in petroleum hydrocarbons having a boiling range of from 80 to 120 C. or in chlorinated hydrocarbons with 1 to 3 carbon atoms such as carbon tetrachloride, trichloroethane, perchloroethylene methylene chloride and so on. In this event, the active substance can be up to of the product of the invention.

The products are well absorbed by the leather and give excellent fat-softening and solftening effects, which possess a notable stability towards water, and aqueous or organic cleaning agent solutions. Their tendency to migrate during thermal stress is very small, so that, for example, bonding processes or the vulcanization of rubber soles on shoe uppers can be carried out without drfiiculty. The good lightand oxidation stability of the products is specially to be emphasized, which makes them also suitable for the fat-liquoring of sensitive and light colored leathers.

The present invention will be further described by way of reference to the following specific examples which are not to be deemed limitative.

EXAMPLE la (I) Batchwise preparation of a chlorination product 600 gm. of a distilled tallow fatty acid methyl ester (11 1.449) were placed in a 1 liter round-bottomed three-necked flask provided with a frit for the entrance of gas, thermometer, stirrer and gas exit tube. Chlorine was passed therein at room temperature with vigorous stirring until hydrochloric acid vapors were evolved. The temperature was maintained especially at the beginning of the reaction, at 40 C. by vigorous cooling.

The flask was then irradiated with a mercury vapor lamp and a further amount of chlorine was passed in. Chlorination was continued until the contents of the flask amount to 845' gm. and the refractive index of the chlorinated ester reached the value 11, 1.482. The product then contained about 29% of added chlorine.

(II) Continuous preparation of a chlorination product For this purpose a gasifying apparatus generally suitable for the action of gases on a liquid media was used. The material to be chlorinated was pumped into the apparatus in the circuit via a cooler. The chlorine was added in a finely dispersed form by an injection nozzle. Initially tallow fatty acid methyl ester introduced into the circuit was chlorinated under the constant action of a mercury vapor immersion lamp dipping into the material until the desired degree of chlorination of 29% to 30% was attained. The temperature was regulated so that a gradual rise of the temperature of 90 to 100 C. (owing to the heat of reaction) took place towards the end of the reaction.

For the continuous process thus starting, the ester at the desired flow rate was fed into the apparatus through a dosing pump and the stream of chlorine and the issue of the finished chlorinated product was adjusted accordingly. In order to remove the hydrogen chloride, the product was passed over a degassing tower which was charged with Raschig rings or similar filling bodies and which was under a vacuum of mm. Hg.

By way of example, when 6.9 kg. of tallow fatty acid methyl ester and 1.8 to 1.9 m. of chlorine per hour were introduced into the apparatus, the desired chlorination product was obtained in an amount of 9.8 kg. per hour.

The process was operated in an analogous way when other fatty substances are chlorinated instead of tallow fatty acid methyl ester.

EXAMPLE 1b Use of the chlorinated fatty acid ester Chrome-tanned and weakly after-tanned upper leather was fat-liquored with 5% of active substance comprising a mixture of 70 parts by weight of a filtered sperm oil chlorinated according to Example 1 of the German Pat. No. 1,278,681 and then sulfated, and 30 parts by weight of the chlorinated tallow fatty acid methyl ester described under Example 1a, and 200% of water at 60 C. for 45 minutes, dried and finished in the usual way.

A light-colored, soft, supple and good light-resistant upper leather with a mild handle was obtained.

EXAMPLE 2 Chrome-tanned and weakly after-tanned upper leather was fat-liquored for 45 minutes with 5% of active substance comprising a mixture of 70 parts by weight of a sulfated, filtered sperm oil and 30 parts by weight of the chlorinated tallow fatty acid ester prepared according to Example 1a, and 200% of water at 60 C., and subsequently dried and finished in the usual way.

A light-colored, soft and supple upper leather with good light resistance and a mild handle was obtained.

EXAMPLE 3 Weakly after-tanned chrome upper leather was fatliquored for 45 minutes with 5% of active substance comprising a mixture of 60 parts by weight of a sulfated sperm oil and 40 parts by weight of a chlorinated methyl oleate prepared according to Example 1a with a chlorine content of approximately 30% by weight, and 200% of water at 60 C., and was subsequently dried and finished in the usual way.

A good light-resistant leather with a full supple and greasy handle, which does not tend to form stains, was obtained.

EXAMPLE 4 A chrome-tanned suede clothing leather was fatliquored for 45 minutes with 7% of active substance comprising a mixture of 7 0 parts by weight of a chlorinated and then sulfated hydrogenated sperm oil prepared according to Example 1 of the German 'Pat. No. 1,278,681, and 30 parts by weight of a chlorinated sperm oil prepared according to Example la having a chlorine content of about 30% by weight, and 143% of water at 60 C., and was subsequently dried, egged, dyed and after-fat-liquored in the usual Way with a 2% of active substance of the same mixture of products.

A cloth-like, soft, good light-resistant and supple suede clothing leather was obtained.

EXAMPLE 5 A chrome-tanned and weakly after-tanned upper leather was fat-liquored for 45 minutes with 5% of active substance comprising a mixture of 60 parts by weight of a train oil sulfated in the usual way, and 40 parts by weight of a chlorinated train oil fatty acid methyl ester with a chlorine content of approximately 30%, and 200% of water at 60 C., and was subsequently dried and finished in the usual way.

A soft, flexible and greasy leather of plump handle, which does not tend to form fat stains, was obtained.

EXAMPLE 6 A chrome-tanned ad weakly after-tanned upper leather was fat-liquored for 45 minutes with 5% active substance comprising a mixture of 59 parts by weight of a chlorinated and then sulfated sperm oil prepared according to Example 1 of German Pat. No. 1,278,681, 30 parts by weight of the chlorinated tallow fatty acid methyl ester of Example la, and 1 part by weight of an epoxidized soya oil having an epoxide oxygen content of 2%, and 200% of water at 60 C., and was subsequently dried and finished in the usual way.

A soft, flexible and greasy leather of plump handle which does not deteriorate when exposed to light was obtained.

EXAMPLE 7 A chrome-tanned and weakly after-tanned upper leather was fat-liquored for 45 minutes with 5% active substance comprising a mixture of parts by weight of a chlorinated tallow fatty acid methyl ester prepared according to Example 1a, 20 parts by weight of an adduct of ethylene oxide to an unsaturated fatty alcohol mixture containing 14 to 18 carbon atoms, and 500% of water at 60 C., and was subsequently dried and finished in the usual way.

A light colored soft and supple upper leather with good light resistance was obtained.

EXAMPLE 8 A chrome-tanned and weakly after-tanned squeezed upper leather was immersed for 1 minute in a solution of parts by weight of acetone and 10 parts by weight of a chlorinated tallow fatty acid methyl ester prepared according to Example 1a at a temperature of 25 C., and was subsequently dried by vacuum and finished in the usual way.

A light-colored, very soft and good light-resistant upper leather was obtained.

The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art may be employed without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A fat-liquoring agent for leather and skins containing from 10% to 50% by weight, of total active substances, of chlorination products of esters of olefinicallyunsaturated higher fatty acids, having from 8 to 24 carbon atoms with alcohols selected from the group consisting of alkanols having 1 to 4 carbon atoms, alkenediols having 2 to 6 carbon atoms, alkanetriols having 3 to 6 carbon atoms, alkanetetraols having 4 to 6 carbon atoms, hexanehexols, alkanols having from 8 to 24 carbon atoms, and alkenols having 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40% by weight, no sulfate groups, and having substantially no free or olefinic double bonds, and from 90% to 50% by weight of total active substances of anionic fat-liquoring agents.

2. The fat-liquoring agent of claim 1, wherein said chlorination product is a chlorination product of a naturally occurring fat or oil.

3. The fat-liquoring agent of claim 1 wherein said chlorination product is a chlorination product of an ester of a fatty acid having from 8 to 24 carbon atoms with an alkanol having from 1 to 4 carbon atoms.

4. The fat-liquoring agent of claim 1 having a further content of from 0.5% to by weight of an epoxy compound for stabilizing said chlorination products.

5. The fat-liquoring agent of claim 4 wherein said epoxy compound is an epoxidized naturally-occurring fat or oil.

6. The fat-liquoring agent of claim 1 having a further content of emulsifiers selected from the group consisting of higher fatty alcohol sulfates, higher alkylsulfonates, alkylbenzenesulfonates having from 1 to 18 carbon atoms in the alkyl, water-soluble ethylene oxide adducts of higher fatty alcohols, and water soluble ethylene oxide adducts of alkylphenols having from to 20 carbon atoms.

7. The fat-liqouring agent of claim 6 having as said active substance from 20% to 30% of said chlorinated products, from 5% to 20% of said emulsifiers, and from 75% to 50% of the usual leather treatment substances from the group consisting of the natural oils, the natural fats, chlorinated paraffins, paraffin sulfonates, mineral oils and mixtures thereof.

8. A fat-liquoring agent for leather and skins consisting essentially of an aqueous emulsion containing from 1 to 10% of active substances, said active substances consisting essentially of from 10% to 50% by weight of the chlorination products of esters of olefinically-unsaturated higher fatty acids having from 8 to 24 carbon atoms with alcohols selected from the group consisting of alkanols having 1 to 4 carbon atoms, alkanediols having 2 to 6 carbon atoms, alkanetriols having 3 to 6 carbon atoms, alkanetetraols having 4 to 6 carbon atoms, hexanehexols, alkanols having from 8 to 24 carbon atoms and alkenols having 8 to 24 carbon atoms, said chlorination product having a chlorine content of from 10% to 40% [preferably from 20% to 30%] by weight, no sulfate groups, and having substantially no free or olefinic double bonds, from 0.5% to 5% by weight of an epoxidized ester of a higher olefinically-unsaturated fatty acid with an alcohol selected from the group consisting of glycerol and alkanols having from 1 to 6 carbon atoms, and from to 50% by weight of conventional anionic fat-liquoring agents.

9. The method of fat-liquoring leather which consist of contacting tanned leather or skins with the fat-liquoring agent of claim 8.

10. The fat-liquored leather produced by the process of claim 9.

References Cited UNITED STATES PATENTS 1,841,990 7/1929 'Ihauss 260-408 1,129,165 2/1915 Buchner 260408 1,165,222 8/1911 Buchner 260-408 2,201,484 5/1940 Farrington et a1. 260408 3,370,005 2/1968 Stein et al. 252-8.57 2,746,838 5/1956 Raecke 8-94.33 2,523,324 9/1950 Putnam 8-94.33

FOREIGN PATENTS 601,114 4/ 1948 Great Britain 260-408 1,278,681 9/1951 Germany.

OTHER REFERENCES McKinney et al.: The Preparation and Same Properties of Chlorinate Lung Oil, Journal of the American Oil Chemists Society, vol. 36, N0. 4, April 1959, pp. -173.

GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner US. Cl. X.R. 

